Slab-debarking machine



May 20, 1930. w. A. DAVIDSON, 1,759,133

SLAB, DEBARKING MACHINE File y 9, 1928 2 Sheets-Sheet 1 gwuenlioac May 20, 1930. w. A. DAVIDSON 1,759,138

SLAB DEBARKING MACHINE F d -Y9, 1928 2 Sheets-Sheet I Patented May 20, 1930 PATENT OFFICE WILLIAM A. DAVIDSON, F ABERDEEN, WASHINGTON SLAB-DEBARKING MACHINE Application filed July 9, 1928. Serial No. 291,287.

This invention relates to machines adapted to remove the'bark from slabs preparatory to using the wood of the slabsfor making pulp for paper-1naking machines.

' The objects of my invention are to provide a machine which will, first, remove all the bark from a slab, thereby reducing thev cost of preparing such slabs for the pulp mill; second, remove said bark without removing substantially any of the wood of the slabs; third, operate on each slab in accordance with its shape; fourth, prepare the end of each slab for the debarking machine; fifth, remove knots from the path of the debarking machine; and sixth, be continuous in its action. A futher object is to provide a continuous chain cutter, adapted to cut downward through the bark to the wood. Another object is to provide a second continuous chain cutter adapted to cut away the bark from the wood as the slab isfed therepast. Another object is to provide a simple means of adjusting the chain cutters whereby they conform to the shape of the slab.

Another object is to provide a machine which is simple to make, easy to operate and control, and which will effectively remove all the bark from the slab.

I attain these and other objects by the devices, mechanisms, and arrangements illustrated in the accompanying drawings, in which a Fig. 1 is an end elevation of my improved debarking machine; Fig. 2 is a side view thereof; Fig. 3 is a plan of the upper control platform; Fig. i is a plan of the lower control platform; Figs. 5, 6, 7 and 8 are views of the first or slab-preparing chain, Fig. 5 being a top plan View thereof, Fig; 6 a side view of the front side thereof, Fig. 7 a section thereof, on the line A'B in'Fig. 5, and Fig. 8 a side view of the rear side thereof; Figs. 9, 10 and 11 are views of the second or debarking chain, Fig. 9 being a top plan view there of, Fig. 10 a side view of the front side thereof, and Fig. 11 a side view of the rear side thereof; Figs. 12 and 13 are perspective views of the side tooth and pivot of the first and second chains, respectively; Fig. 14 is a similar view of the shoe of thesecond chain; and

Figs. 15 and 16 are plans showing a slab being prepared by the first chain, and being debarked by the second chain, respectively.

Similar numerals of reference refer to similar parts throughout the several views.

It is well known that it is necessary to entirely remove the bark from a slab before the wood thereof is available for use in a pulp mill. Various machines have been devised for this purpose but such machines have usually been adapted for the small timber of the east em or central States and are entirely impractical for use on the slabs cut from the heavy timber common in the western forests, especially as the bark thereof is often of greatly varying thickness.

In the following described machines, it will be understood that such parts and mechanisms as are in common use at the present time, are omitted. For instance, the feed mechanism whereby the supporting and holding-down rolls are controlled and actuated to feed the slab through'the machine, or to hold it stationary while being prepared for the debarking chain, or while having a knot removed, is entirely omitted, the rollers alone thereof being shown. Also it will be understood that thermeans shown herein is often intended more asa diagrammatical illustration of the idea than as a specific mechanism, for instance, the hand and footlevel mechanisms for controlling the friction drives and the brakes, may be'substituted by pneumatic or other apparatus such as is in common use in sawmills for purposes of control.

Referring now to the drawings, the slab 1 to be debarked is supported on a series of feed rollers 2 and is fed through the machine thereby to the delivery rolls 3, (Figs. 1, 2, 15 and 16 The frame of the debarking machine itself comprises a pair of upright posts 4;, one on each side of the slab-feed channel formed by the rollers 2 and 3, in the center of the machine. These posts 4 are provided with suitable other structural members and carry the cutting chains and their operating and controlling mechanisms. v

The first, or slab-preparing endless chain 5 comprises four series of links arranged in' pairs separated by a distance of about three inches. The links 6, forming the first or front series, are all provided with two inclined grooves in their outer surfaces, adapted to receive the heads or teeth '7 which form the side cutters of the chain and which extend from the front sine thereof. These grooves are near the ends of the links 6, and a pivot hole is provided in suitable position in each groove.

The inner links 8 are provided with two pairs of holes therethrough, the left-hand hole (Figs. 5-7) corresponding to the above pivot holes in the grooves in the links 6.

The outer, rear, links 9 are provided with a single pair of holes, corresponding in position to the said holes in the above links 6 All the links 6, 8 and 9 are provided with sharp cutting teeth 10, extending downward from their lower edges, (Figs. 5 and 8).

The pivots 11 (Fig. 12) are provided with said cutter heads 7, integral with one end, and pass through all sets of links of the chain 5. from side to side, and are provided with suitable retaining means, such as the cotter pins 12 through the rearward ends.

The two sets of inner links 8 are separated by means of suitable cylindrical separators 13 (Figs. 5 and 7) and by similarly shaped cutters 14. each of which is provided with a tooth 15 extending downward therefrom in line with the above mentioned teeth 10 on the lower edges of the links 6, 8 and 9. The separators 13 and the cutters 14 are provided with two holes therethrough. The pivot pins 11 pass through the left-hand hole while the shorter pins or rivets 16 pass through the other holes therein and in the inner links 8.

As seen in Fig. 5, the cutters 14 are placed to bring their teeth 15, in successive links of the chain 5, in successively displaced lateral positions, each cutter occupying a small width of chain and all cooperating to cut the full width thereof in conjunction with the teeth 10 on the links thereof.

The heads 7 are provided with suitable cutting edges 17, as shown, adapted to cut down ward in the bark of the slab.

The chain 5 is mounted on the driven wheel 18 (Figs. 2 and 3), and passes through the machine, first horizontally from the said wheel 18, then over the take-up wheel 19 (Figs. 1 and 3) and under the two independently adjustable guide wheels 20 and 21, and thence back to the driving wheel 18.

The sliding or take-up wheel 19 is mounted on a carriage 22 adapted to move horizontally on the arm 23 of the frame, and the tension of the chain 53 is maintained by means'of a weight 24, pulling outward on said carriage 22.

The adjustable guide wheel 20 is mounted on a carriage 25 moving vertically in slots in the posts 4 of the frame. The position of the carriage 25 is controlled by the vertical chain 26, which passes over the upper driven wheel 27 and the lower idle wheel 28 on the post 4. The upper wheel 27 is mounted on the shaft 29 (Figs 1 and 4). A brake drum 30 is mounted on the shaft 29 and is of any desired construction, and is operated by any suitable means, such as the cable 31 and the pedal 32, to hold said shaft 29 from rotating when the pedal 32 is depressed, but to permit it to rotate when said pedal is released.

The shaft 29 is rotated by a short chain 33 passing over the wheel 34, mounted on said shaft, and over a driven wheel 35 on the upper control platform of the machine. The driven wheel 35 is mounted on a short shaft 36. One end of this shaft 36 is movable laterally by means of a lever 37 and link 38 engaging its bearing 39 (Fig. 1), said lever being actuated in any desired manner as by the cable 40 and the hand lever 41, or by pneumatic means as above mentioned. and acting against a retracting spring 42. A large friction wheel 43 is also mounted on the shaft 36 and is adapted to be brought into contact with the driven friction wheel 44 the motion of the bearing 39 caused by the lovers 37 and 41.

The machine mav be driven in any desired manner and is illustrated diagrammatically by the belt driven pulley 45, mounted on the short cross-shaft 46. This shaft 46 drives the main cross-shaft 47 by means of the chain 48 passing over the wheels 49 and 50 mounted on the said two shafts respectively.

The main cross-shaft 47 is provided with the abovementioned friction wheel 44 mounted thereon. The driven wheel 18, over which the first chain 5 passes, as above described, is mounted on a short shaft 51. This shaft 51 is driven by means of a short chain 52 passing over wheels 53 and 54 mounted on said shaft 51 and on the main cross-shaft 47, respectively. Thus it will be seen that the chain 5 is continuously driven through the parts 45, 45, 48, 47, 52 and 51.

Thus, also, it will be seen that the normal position of the guide wheel 20, on the post 4, is at the upper end of its travel, as seen in Fig. 1, under the action of the weight 24, but that it can be moved down therefrom to any position on the post- 4 by operating the hand lever 41 to cause the friction wheel 43 to engage and be driven by the constantly rotating friction wheel 44, thus actuating the chains 33 and 26 to move the carriage 25 downward against the tension in the chain caused by the weight 24. hen the carriage 25 has been thus brought to the desired position the hand lever 41 is released and the brake pedal 32 is depressed to grip the brake and to hold the carriage in such adjusted position.

The guide wheel 21 is similarly controlled by means of the opposite friction wheel and cally below the plane of the chain 5, and is held in this position. Then the chain 5 is lowered by lowering the carriages of both the wheels and 21, as above described, to

. the desired positions and so that the chain 5 will cut downward through the soft bark of the slab 1. It is of course understood that since these wheels 20 and 21 are independently controlled, they can be brought to occupy any positions,-thus permitting the chain to conform to the shape of the slab, as it cuts therein.

As soon as the bark has been thus removed from the end of the slab 1, the brake pedals 32 are released and the weight 24 draws the chain 5 up out of the way by causing the carriages of the wheels 20 and 21 to slide up to their uppermost positions (Fig. 1).

The main debarking chain 56 (Figs. 1, 2, 3, 9, 10, 11, 13, 14 and 16) comprises two sets of outer links 57 and two sets of inner links 58, suitably secured together as hereinafter described.

The outer links 57, of the debarking chain 56, are provided with two inclined grooves near their ends and with holes through said grooves. The inner link 58 have corresponding holes through their ends. Separators 59 have corresponding axial holes therethrough and are mounted between the inner links 58 of each pair. The pivot pins 60 (Fig. 13) are provided with heads 61 which are adapted to lie in said grooves in the outer links 57, on the front side of the chain. These heads 61 are shaped to form side cutting teeth extending sideways of the chain. Shoes 62 (Figs. 9, l1 and 14) provided with suitable holes therein, are mounted in the grooves on the rear side of the chain 56, and extend downward therefrom to a level with the points of the cutting edges of the cutting heads 61. Each pivot pin 60 passes through the four rows of links, the separators 59 and the shoe 62 and is provided with a suitable lock such as the cotter pins 63.

The above endless chain 56 is mounted onthe rear side of the posts 4 and is actuated by the driven wheel 64, mounted on the above-described shaft 46 (Fig. 3) and thence passes over a take-up wheel similar to the above-described wheel 19 and under twoguide wheels similar to the above-described guide wheels 20 and 21 and mounted on the rear side of the posts 4. The said guide wheels are controlled and held exactly as are the said guide wheels 20 and 21. The operation of the control of said chain 56 is exactly similar to that already described.

The slab 1 is fed forward until the end thereof,.prepared by the chain 5, as above described, lies under the chain 56, which is then brought down into operating position (Figs. 1 and 2). The slab 1 is then fed forward continuously by the rollers 2 and 3, and as it advances the teeth 61 cut away all the bark from its surface, thus preparing the slab for use in the pulp mill. 7 The shoes 62, which ride on the surface of the wood, and not on the bark, prevent the cutting teeth 61 from cutting any of the wood of the slab away.

It is evident that the two chains 5 and 56 may be run at different speeds, if desired, by changing, for instance, the proportions of the wheels 49 and 50 to the wheels 53 and 54.

7 It is also evident that many changes may be made in the details of such a machine, without in any way changing its main idea, as outlined in the appended claims. r

Having,therefore, described my invention, what I claim is 1. In a debarking machine, the combination with means adapted to feed the slab through the machine; means adapted to debark the front end of the slab; a continuously moving flexible chain adapted to engage the slab at said debarked front end; means adapted to permit said chain to conform to the shape of the slab; teeth on the front edge of said chain and adapted to cut the bark thereof as the slab is fed through the machine; and means adapted to prevent said chain from cuttin into the slab.

2. fri a debarking machine, the combination with means adapted to feed the slab through the machine, said feeding means maintaining the slab at a constant level; a con tinuously moving flexible endless cutting chain; fixed rotating means supporting a portion of the chain at a fixed level; slidable take up means supporting a portion of said chain at fixed level but at varying distance from said fixed supporting means; two sets of vertically adjustable guiding means engaging the chain, one on each side of said feeding means, adapted to guide the chain to or below the level of the slab, whereby the chain is caused to engage the top side of the slab and to conform itself to the curvature thereof, whereby the bark on the top side of the slab is removed; and cutting means mounted on said cutting chain.

3. In a debarking machine, the combination with a frame; a fixed rotating wheel mounted thereon; two vertical guide slots formed in said frame; carriages mounted in said guide slots; two guide wheels mounted on said carriages; means for'independently adjusting the position of said carriages in said slots; an endless cutting chain passlng around said fixed rotating wheel and said guide wheels, and longer than the distance around said three points of support; and a take-up wheel, slidably mounted in said frame and adapted to take up the slack in said chain.

4. In a debarking machine, the combination with a frame; a fixed rotating wheel mounted thereon; two vertical guide slots formed in said frame; carriages mounted in said guide slots two guide wheels mounted on S21i carriages; means for independently adjusting the position of said carriages in said slots; an endless cutting chain passing around said fixed rotating wheel and said guide wheels, and longer than the distance around said three points of support; a take-up wheel, slidably mounted in said frame and adapted to take up the slack in said chain; and means drawing said takeup wheel away from said fixed wheel, whereby the slack in said chain is automatically taken up.

5. In a debarking machine, the combination with a frame; a fixed rotating wheel mounted thereon two guide wheels vertically adjustahly mounted on said frame; an endless cutting chain passing around said fixed rot-ating wheel and said guide wheels, and longer than the distance around said three points of support; a take-up wheel, engaging said chain and forming a fourth point of support thereof, and slidably mounted in said frame; a weight; and a connection between said weight and said take-up wheel, whereby the weight applies a constant force to said takeup wheel to take up the slack in said cutting chain.

6. In a debarking machine, the combination with a frame; two vertical guide slots formed in said frame; carriages mounted in said guide slots; two guide wheels mounted on said carriages; a slab feed channel mounted betweensaid guide slots; means for independently adjusting the position of said carriages in said slots; and an endless cutting chain passing under said guide wheels and over a slab on said feed channel to cut the bark therefrom as the slab is fed past said chain.

7. In a debarking machine, the combination with a frame; a vertical guide slot formed in said frame; a carriage mounted in said slot: a guide wheel mounted on said carriage and adapted to guide a transverse ly moving cutting chain thereon; a driven wheel; an idle wheel; a second chain passing around said driven and idle wheels and secured at its ends to said carriage; and means adapted to drive said driven wheel, whereby the carriage and guide wheel are adjusted on said frame.

8. In a debarking machine, the combination with a frame; a vertical guide slot formed in said frame; a carriage mounted in said slot; a guide wheel mounted on said carriage and adapted to guide a transversely moving cutting chain thereon; a driven wheel; an idle wheel; a second chain passing around said driven and idle wheels and secured at its ends to said carriage; means adapted to actuate said driven wheel, whereby the carriage and guide wheel are adjusted on said frame; and braking means adapted to hold said driven wheel from motion, to

hold said carriage and guide wheel in adjusted position on the frame.

9. In a debarking machine, the combination with. a frame; a vertical guide slot formed in said frame; a carriage mounted in said slot; a guide wheel mounted on said cariage; means for moving said carriage lownward in said slot; releasable means for holding said carriage in such adjusted position: a cutting chain engaged by said guide wheel and adapted to be pressed down on its work thereby; and a tension means acting or said cutting chain and adapted to resist said downward pressure of the guide wheel, and whereby when the guide wheel is released said chain will raise the guide wheel and be removed from working position.

10. In adebarking machine, the combination with a frame; a vertical guide slot formed in said frame; a carriage mounted in said slot; a guide wheel mounted on said carriage; a constantly rotating friction wheel .iounted on said frame; a laterally slidahle friction wheel adapted to he moved into or out of contact with said first friction wheel; a driven wheel operatively connected to said second friction wheel; an idle wheel; a chain passing around said driven wheel and idle wheel and secured at its ends to said carriage, whereby when the friction wheels are in contact said guide wheel is moved downward on said frame; a cutting chain engaging said guide wheel and pressed downward thereby; and manual means adapted to c011- trol the position of said second friction wheel, whereby when said manual means is actuated said friction wheels are broughtinto contact.

11. In a debarking machine, the combination with means for feeding the slab through the machine; a continuously moving flexible cutting chain; a take-up wheel over which said chain passes; means for actuating said take-up wheel to retain the tautness of said chain; two separate and independently adjustable guide wheels mounted on each side of the slab-feed channel, and under which said chain passes; means for vertically adjusting each said guide wheels; means for holding each said guide wheels in adjusted positions; shoes on said chain and adapted to engage the wood of the slab to prevent the chain from cutting therein; and teeth on the front side of said chain, whereby said chain cuts the advancing bark from the slab as it is fed thereunder.

YVILLIAM A. DAVIDSON. 

